#include<stdio.h>
long f(int g)
{
    switch(g)
    {
        case 0:return 0;
        case 1:
        case 2:return 1;
    }
    return (f(g-1)+f(g-2));

}
int main()
{
    long k;
    k=f(7);
    printf("k=%d\n",k);
    return 0;    
}